OBJECTIVE: To identify the desired features of end-of-life medical decision making from the perspective of elderly individuals. DESIGN: Qualitative study using in-depth interviews and analysis from a phenomenologic perspective. SETTING: A senior center and a multilevel retirement community in Los Angeles. PARTICIPANTS: Twenty-one elderly informants (mean age 83 years) representing a spectrum of functional status and prior experiences with end-of-life decision making. MAIN RESULTS: Informants were concerned primarily with the outcomes of serious illness rather than the medical interventions that might be used, and defined treatments as desirable to the extent they could return the patient to his or her valued life activities. Advanced age was a relevant consideration in decision making, guided by concerns about personal losses and the meaning of having lived a "full life." Decision-making authority was granted both to physicians (for their technical expertise) and family members (for their concern for the patient's interests), and shifted from physician to family as the patient's prognosis for functional recovery became grim. Expressions of care, both by patients and family members, were often important contributors to end-of-life treatment decisions. CONCLUSIONS: These findings suggest that advance directives and physician-patient discussions that focus on acceptable health states and valued life activities may be better suited to patients' end-of-life care goals than those that focus on specific medical interventions, such as cardiopulmonary resuscitation. We propose a model of collaborative surrogate decision making by families and physicians that encourages physicians to assume responsibility for recommending treatment plans, including the provision or withholding of specific life-sustaining treatments, when such recommendations are consistent with patients' and families' goals for care.